Determine scripton sizes for the individual size classes of HnRNA, for polyadenylated nuclear and cytoplasmic RNA, halflives for HnRNA by size class, and HnRNA/messenger RNA precursor relationships; scripton sizes for hemoglobin and H and L chains of IgG proteins. Investigate the genetic causes for variant production from Merwin plasmacytoma cells, MPC 11, defective in H or L chain synthesis. These objectives are part of the broader goals of: (a) understanding the transcriptional organization of eukaryotic chromosomes; (b) understanding the biological role of that part of HnRNA (30s to 50s) which might not be a precursor to HnRNA; (c) understanding synthetic and degradative rates and kinetics for all cellular RNA (except structuaral and transfer RNA); (d) understanding possible mutational and recombinational steps that might contribute to antibody diversity (by a study of aberrant H and L chains in variants of MPC 11); (e) probing into a conceivable interrelationship between variant production from MPC 11 and chromosomal disorders in bone marrow cells of leukemic patients during the initial phase of leukemic development (i.e., before drug and radiation treatments).